The last 30 days in Stockholm (Bromma airport), Min. temperature so far -3.5ºC
http://www.ogimet.co...&min=0&ndays=30
and the last 30 days in Sofia (Bulgaria), Min. temperature so far -10.8ºC
http://www.ogimet.co...&min=0&ndays=30
Personally I am not surprised, because many years Sofia records temperature lower than Stockholm.
The lowest temperature ever in Sofia was -31ºC versus - 32ºC in Stockholm. Almost the same.
There are people in this forum that ignores what the climate of Eastern Europe is.